Conversion apparatus



July 8, 1947.

CONVERS ION APPARATUS 3 Sheets-Sheet 2 Filed Jan. 2e, 1942 ,qv/mms usr mm y message cwvneoL` d,

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cCNvERsIo APPARATUS A Filed Jan. 26,v 1942 y":s sheets-snm s was .sm WH TWK Numa, fm r /N MA be@ @f Patented July 8,1947

oNvnsIoN APPARATUS "John D.' Aken-man and AJean F. riccaafminne. apolis, Minn.,A assi'gnors to Regentsvo! theA University oi' Minnesota, Minneapolis, n Minn.,` a

' corporation ot Minnesota -z-Appueauoegaqwy 26,1942, sexisme. maso (fonce-1) This invention relates to an'apparatus forfcofi' verting oxygen from thejliquld phase to the 'gase ousvphase at a variable-ratein 'accordance with a; variable demand for the 'zgaseousloxygen '-w f The provision of gaseous oxygen forr useinf hospitals; aviators masks, land forlanalogou's' uses has long been accomplished by utilizing gaseous-.- oxygen compressed under highr pressure into metal bottles of great strength. `In'order' to pro'- vide a reasonable amount Vo oxygen for breath' ingpurposes in arr airplane, for example, it is' necessary to utilize pressures from. 400 to,2,000

fpounds perY square inch intheroxygen bottle', and even with suchf equipment, theamount of gasA oxygen that may befstored'r under pressure is limited. In orderk to provide suicient-oxygeni for one man for two hours atf30000 ieetaltitude,

an oxygen bottle 13%, inches lo'ngand;` inches in diameter must be used if the pressure isj-1800 pounds per squarefinch. Suchabottle is, Vhowever, under tremendous ,stress 'andif-hit by a machine guny bullet, it will"fregu`ently explode obiect-of the invention to provide anexceptionaiilyrugged and stable apparatus capableofbeing .used Iin.-.militaryaircraft unaffected b'y gnreior' theprovision of oxygen v forfhllman respiration.l

` Othi-ir-and further oblets loftltuelriventionjare those` inherent' in. theV methods and apparatus hereinidescribeagi11ustrated and claimed.

1 'The invention isillustrated with reference to the drawings in which:

Figure l isfa schematic illustration of an appalratus embodying theinventio'n,` and capable oi U- the invention'V in which., Figure '7 is a schematic. Asideelevation partly in section, Figure 8 is a schea', maticend view partly in section, and Figure 9 is bottle lsl800 pounds per square inch, and only T45 'liters of oxygen (measured .atnormaP pres sures and temperatures) when the pressurer within the bottle is 400 pounds per square inch.

, One liter or liquifled oxygen, on the vother hand,V produces 1880 liters of gaseous oxygen forapproximately'8%'hours at 30,000 feet. K

It is'an object of the present invention'to provide methods and apparatus jfor convertingy liquied 'oxygen to vgaseous oxygen in accordance wlththe vvariable demand andin a manner such that it is suitable for human consumption for respiratory purposes i It is afurther object of the invention to provide :I Y methods and apparatus for convertingoxygen from the liquid to the gaseous phase -inaccordance with' the Variable demand and under pressure for use either in aviationinstallationshos- -pital installations, or at oxygen depots where oxygen gas cylinders ar'efilledunder high prese 66 sure from existingliquidbxygenstores;Vv

j i carrying .out themethods of the-invention;

` Y Figure-2isaschematicillustration of another,

formqof the apparatus of the invention capable of carrying 'out the methods of theinvention;

, Figure Svis a schematic view partly in vertical fsectionillustrating one form of apparatus of the present invention; 2o`

A section illustrati'ganother form of the invention;

Figure 451s a schematic View partlyin vertical Figures 5 and 6 are fragmentary sectional views ofthe valvingapparatus usedin the apparatus of Figure 4 and illustrating adjusted positions;v Y l l f d Figures 7,8and QTilustrate-another form of a schematic plan view partly in section.

, Figure 10 is a fragmentary view of afmodiiied y ,form of filling apparatus. I u l Y The methods of thenpresent invention may be `,carried out linr a variety of apparatus of which l illustrative embodiments rare shown herein.y

Referring toiFigure 1the apparatus ofthe invent-ion comprises lan outer pressure container -f (measured at Y normal pressures 1 and Ytemperatures); and this amount is suilicient forjone man I0 having an oxygen withdrawal port II from which the gaseous oxygen 'is Withdrawn as desired forrespiratorypurposes. It is to be understood thatportA I I is connected to a standard pressurereducing valve so that a pressure of predetermined amount is maintained in container I0. In this connection, it will be realized that the respiratory requirements of an aviator vary widely as the i altitude of' thecraft varies from sea level to ceiling whichV may be 30,000 feet or more. Accordingly, the rate at which oxygen is withdrawn from port II varies widely. Within the container Ill,v there 1 is a'smallerpressure container I2 in which liquid oxygen is stored. Container I2 is supported in any suitable manner and is preferably, provided with an\inlet tube I3 extending through the upper the valve in several wall N of container I0, the neck I3 being provided i l cover such as Y bellows is not suiliciently strong. The bellows is connected to the operating arm. 2| of a shut-ofi valve, generally designated 22. The Yvalve 22 is in an outlet tube 23 of the inner container I2 and in the position shown in Figure 1, the valve 2221s in the off position. However, when the bellows expands so as to bring the-operating arm 2i into vertical alignment with the tubealong theaaxis 24, the valve is opened. Y

' Y The apparatus illustrated in `Figure 1 operates in thel following manner illustrative of the methods of this invention:

.Liquid oxygen is initially poured into the inner "container through neck I3 and stopper or cover.

Y I5 is then firmly placed into or on-` the neck ef- Y fectively preventing Yescape oi.' gaseous oxygen through the neck. Y The heat normally inilowing Vthrough walls I vand VIZ'determines thenormal minimum rate of Vevaporation ofthe oxygen in Y 4* i plugged .by any suitable stopper .or cover I 5'. Within pressure container I0', there is a Sylphon bellows so as to close the vent tube 23 of the liquid oxygen container I 2' when the Sylphonbellows is expanded. An over-pressure release valve, generally designated I B is provided for the liquid oxygen container, and there is also provided a tube Yextending from the'lower portion of the liquid oxygen container to the upper wall thereof and bent downwardly and terminatingabove the maximum level of the liquid oxygen within the container I2. The operation of the apparatus shown in FigureZ is as follows: Y

The liquid oxygen container I2' is lled by removal of stopper I5', which is then immediately re-insertedv andrernains in place during normal operation. The SJylpho-n bellows 20 may then be collapsed thus opening vent 23' allowing the oxygen vapor to escape to container I0', but if the bellows is in the positionshown in Figure 2, pressure builds-up within the liquid oxygen Vcontainer I2' and causes the liquid4 oxygen level to rise in tube 25' thllsfperl'ntting rliquid.'oxygen tovsplll tainer. The amount of liquidoxygenspilled over y `reservoir I2 andlas the gas pressure within` I2 n I `builclsfup,.it will `i'roxri-tiim'e, to time open the overpressure valve i I 6 allowing the oxygen Yto pass,

through the Vvalvelinto'container I0 thereby establishing and maintaining a pressure within I0 provided the withdrawal `ofgaseous oxygen at port II is not greater than the minimum Vrate "of evaporation in the system. Thepressure normally maintaining within the container l Il is sufiicient to compress the Sylp'hon bellowsll tothe on position shown in Figure 1 thereby holding "the Vvalve 22 in the closed position. However,

when gasis withdrawn from port Il such asfor respiratory purposes and thegaseous oxygen pressure within container I0 is thus reduced'sylphon bellows 20 expands and opens valve 22thus permitting liquid oxygen to befspilled directly from III produce rapid evaporationof theliquidV oxygen over into the container lll where it is quickly vaporized dueto the large heat inputto the conis suicient togsupply the maximum demands for oxygen withdrawal from tube Il" and establishes `a predetermined pressure withinthe container I Il'. "Sylphon, bellows isadjusted s'o as to contract at'a predetermined pressure. thus drawing the valve plug 22' away Vi'ror'nthe upper end of vent tube 23,', Y Y Y Y Y The oxygen normally` evaporated` within the vliquid oxygenontainer I2' passes over through the vent 23 unt-il` such timeas the vent isagain closedV due to a decrease in pressure in container |U".as occurs whenV gaseousoxygen is withdrawn -frornrtube- Ilf. So long as ithe valve plug 22 is lifted on of-tube 23',.1iquid oxygen withintube 25" remains at the level of the liquid oxygen `in the storage tank I2', but whenever the vent 23 is f closed responsive to a decrease in pressure in the Y, gaseous oxygen storage tank YI Il', the oxygen which is evaporated in storage tank I2 at a minimum irate gradually builds up the pressure and gradually forces liquidoxygen'upwardly in tube 25 Acontainer I2 into'container I0. The much great- Y ter available heat supply of the walls of container i thereby quickly reestablishing 'the normaloperating pressure within container IOwithr consequent compression of bellows 2I'I.A This closes the valve 22 and prevents'further spilling of oxygen: from'container I2 into container` II).V This i 'operation is automatically repeated from time to time whenever the pressure within" container Illliis reduced below the adjusted minimum for which the Sylphon bellows and valver22. are adjusted. Suitable adjustments mayv obviously be provided,` both'for varying the operating pressure at whichrSylphon bellows'20 operatesivalve 22, and the pressures at which over-pressure valves I6 and Il are opened.

In Figure 2, the general arrangement-is similar to that illustrated in Figure l-andcomprises an g outer gaseous oxygen `container III' having a gas i withdrawal port II and an over-pressure valve I1. It is to be understood that in service, port Il is connected to a standard pressure-reducing valve so that eventhough gaseous oxygen is withi drawn, a predetermined pressure is maintained in tank I0'. From the upper wall I4', there issuspended an inner liquid oxygen container I2',

which has a iiller neck I3', which is normally whence'itris again spilled over into the tank I0' and quickly evaprated thus again causing the contraction of the bellows20-'L This action is automatically repeated over and over again so-long as,` the liquid oxygen supply is availablein the tank I2. The over-pressure release valverI'I is adjusted so as not to open until ay pressureV greater than the `normal operating pressure of the tank I0' has been exceeded. Thcgover-ipressure valve I 6 is likewise adjustedso that'it does-not open until such a pressure isgenerated within the tank I 2 as might occur if the tube 25 becomes plugged and the valve 22'-23' simultaneously clogged.

Referring now to Figure 3, the apparatus illustrated includes Van aviators oxygen mask, generallyvdesignated 30,- Whichis connected by supgenerally designated 32'..

ply tube 3l to the aviators mask-pressure gauge, y The ygauge is in `turn connected to the mask-pressure control valve,

`generally'designated 33.1 These elements, the

' mask 30, themask-pressure gauge 32 and maskpressurecontrol 33, illustrated under thebracket A,-,do not in themselves form: any part of the present invention, but merely illustrate a common situationrin which the methodrand apparatus of the present invention give exceptional servicefand Y f have exceptional utility.

The apparatus illustrated in Figure 3 comprises agaseous oxygenV pressure sto-rage tank, generally designated 35, having a curvedr bottom wall and cylindrical sidewalis'al. "The tank' is providedy With feet, 38', where' a is bonomfmounted, my

Vbe provided with any suitablebr'acket Afor .wallf mounting. ".The cylindricalsidewalls 81are`p`ro- Vvided with a heavy flanged!) 'which' forms "a seat for gasket 4l upon which ther cover,` generallyv V designated 42,?res`ts.v The' c ove'rois heldin place by a plurality of?screwclamps, generally designated 43,'which maybe swung fdownzout of enr gagementwith the cover when-thev apparatus is Y' disassembled.

Within the containerVV 35,' there is positioned a yframeworkv 45 of perforated metal,A wire cloth,

spaced rodsor the likefof generallycylindrical shape and smaller than vthecylindrical'sidewall so as to form a space in which a'heavy layer of insulation 48 of mineral wooLka'pok orthe likeis situated. They frameworkf45 serves as Ya `'oonvenient support' for holding the relatively? loose and fluffy insulation inplace, and the'frame and insulation are adapted toremain Within thejco-ntainer 35 when the apparatus; mounted upon cover l42, is lifted o'uti' f Cover42 isA provided with a gas outlet tube'48.

i Vwhich .may desirably contain a lter' 49 of silica gehactivated carbon 0r both. If desired, the illv ter 49 may be in the form ofa package capable of being inserted `fromeither the inside orthe outside of outlet tube 48. `Theetube 48 isftted with *f al T 50 having the outlet 'portion 5| 'connected t) the aviatorsY mask-pressure control valve`33.

The T also has connected to it an adjustable over-pressure` relief valve;y generally designated 52-,-h aving anvoutlet hole 53 'and an adjustment screw 54-whereby thefloading Yof' the overpressure valve 'maybeivaried for varying the pressure at which excess oxygen is exhausted. The outlet hole 53 is somewhatfrestricted ascompared with the size of pipe 83,va1ve 80,pipe118, T 16, and` pipe 11, so that'vvhenoxygen` gasiis exhausted at hole 53, there Willnot be' a diierential pressureY established between tank 65 and'tank 35. YStated v another' way, port 53,;when openexhausts rnot onlytheoxygen Agas reservoir 35, butl also: the

oxygen .gas .space above the liquid oxygenfin tank 65. Hence, the Yoxygen lgas flowinggthroughpipe l 83,' valve 8 0,fpipe 18, 1- 16 and pipe 1 1 and thence exhausted via reservoirv 35andivalvel 52, prolduces a pressurediferentialfbetween tanks. 65

and y35, which might cause liquid oxygen to be Byfrnaking hole 5 3 smallas com` spilledover. y pared with the pipes 83 valve 80 and pipe118, the pressure drop through the platter iss kept small.

. Valve 88 should,Y of coursefneverbe adjusted to be closed-'at a pressure above Atlielopening pressure of .valve 5.2, Also valve-52may, as an added precaution, be placed on filler neckk 58, ify desired. Cover 42 is lalso provided with la second Yover.-Y

pressure 'va1ve, generally designated 55, which is of the ordinaryspring-loaded type, .this latter valve being set for a highervpressure than valve 52 so`as to constitute an added precaution against rupture of the apparatus; The cover is ralso p rovided with a tankepressure gauge, generally des- 'ignated 56, calibrated in any desired scale'.

At approximatelythe centerof theftank cover 42, thereis anintegral or assembledupwardneck 58 threaded on the inside at. 5.9 where it receives correspondingly threadedtube 80. The tube 60 is locked inplacev by lock nut 6| which seats against the washer '62. The'tube 60 extends downwardy Aly-into thetank 3 5'andca'rries`the liquidoxygen storage tank generally designtaedBS, having the vupper Awall `66. cylindrical sidewall 8,1 and the n' Vbottom wal1`88.. 'Iheupp'er Wall' Provided with ann insulated cover .1.8. preferably of nbre e board, and of a diameter so as to match with'the 'outer diameter of theinsulation .layerv 4 6. kThe container; 85 is pressure-'tight and is assembled in pressureftight relation to the lower endk of tube 8U..Whichlattervthusconstitutes. a filling tube yfor pouring liquid oxygen into container 65, and also vals,asupporltby which thev container is hung from 1 the cover 42. A'liquidA oxygen'` spill-over tube 69 of tank 65'extends from `nea-'r the bottom-Baupward along wall 61, through the cover '66. and

, 4thence' through a groove in the upper edge of the `thefneck"58,but also lservesas a mounting'for framework`45 and insulation 46 to the space 1lr A between'the insulation 46 and the cylindrical wall 310i the' gaseous oxygen sto-rage tank. An over'- 'pressure .relief valve. 12 is' provided` for the liquid oxygen storage tank.` Theupper portionl of 4neck A58 is threaded. to receive the cover plug, generally designated 13, .which not yonly serves to stopper the spiral-type liquid levelgauga generally desighated 14, having an indicator needle 15 visible. ,througha dial in the upper portion ofthe plugk The spiral-type liquid level gauge may be o-frany well-known construction such as used for l gasoline tanks and the like. i

The cover 42 is also provided with a tubular junction T, generally'designated 1li,v from which jthere extends a tube 11,l bent to extend downwardly, through Vthe insulating cover 18,-and

thence fdownvvardlyalon'g the outside of the llilluid oxygen storage tankwall 61. ,If desired, the tuhe`11- ma'y be soldered in place on the Awall 161 for adding strength and rigidity to the assembly.

From'the -Tf16,.there Valso extends a ktube 18, Vwhich is connected to the diaphragm side of a ldiaphra'gm-operatedvv automatic control lvalve,

e, cludes a connectionby means of tube 8l, whichV generally designated 8 8. lThe valve '80 also in- .is controlled rby shut-olf Avalve 82 and connects with the Ti 16. The valveY further includes a conf erably provided with suitable adjustment yso that Y 1 `nection byimeansof tube 83 to the fil-ler neck 58.

vValv'e includes a diaphragm 84 which is loaded by meaiisofspring 85. Thespring is prefthe operating pressure of the valve may bev varied.

:Within the valve-housing, there vis anantrum chamber 86 having a valve port 81 situated so as ".tobe closed by the diaphragm operatedplug 88. When thepressure on the bottom surface of diaphragm 84 is suicientlylo'w, springf 85 forces Vthe' diaphragm downwardly and forces valve 88 into aperture 18,1 thus closing"r the automatic valve. When; the pressure on Ythe lower side oi"V diaphragm 84has increased to afpredetermined amount (depending upon' the adjustment of the valve)' diaphragm 84 is flexed upwardly thus openin'gValve port 81. vThe automatic valve 80 is then in the position shown in Figure 3. Since the gaseous oxygenmay freely pass through insulation 48 and framework-45, thepr'essure within the storage tank is uniform throughout'and is impressedth'rough tube 11, junction T 16, tube `18 uponthe underside of diaphragm 84.

" The apparatus illustrated in IEigureSr operates f according to the following method:

It is assumedthat the'apparatusihas no liquid `oxygen Withinv container 65 and.. is therefore at ambient `temperature which is vii/arm.Y as compared with ther` temperature 'or liquid" oxygen.

. Ther filler neck'plug 13 (and attached liquid level gaugef14) are removed from thel llei` neck v58"and a quantity of liquidv oxygen is poured through the ller neck Vthus filling or partiallyV filling the liquid oxygen storage tank 65.` The valve 82 is moved to the openposition'; adjustable over-pressure valve 52 isV moved to a position so as to permit exhausting of Y oxygen at comparatively low pressure andv the cover plug 13 and attached gauge are again inserted and-made fast. Valve 82, being open, provides a by-'pass of large capacityso that the comparatively large amount of gaseous oxygen generated due to the sensible heat of the apparatus, will not overwerk valve 80.` Atfirst, there is a-comparative large evaporation of liquid oxygen and the gaseous oxygen passes up through the ,filler neck tube 83, by-pass tube 82, junctionA T` 16, and tube Tl 'to the space between the liquid oxygen storage tank 65 and'the framework 45. The gaseous oxygen then lters outwardly in a comparatively luniformV manner through the insulation layer 46 andA thence, after building up a pressure within the gaseous oxygen storage Ltank 35, it is exhausted through lter 49 and is either consumed at the oxygen mask v3l) Vor is exhausted through the over-pressure relief valve 52.. The valve 52 is 'then adjusted so as to build up the desired `pressure within the tank 35, the pressure being 18 to the T 16, and the `gas flow continues so long as automatic valve'80 remains open. i

For aviation uses, such as high altitude flying.

" it is desirableto build up a pressure of approximately 60 pounds per square inch, absolute,\within the tank" 35 so as to provide a uniform pressure upon the liquid oxygen and hence a uniform vaporization temperature. This is desirable to in decreasing the rate of heat inilowto the liquid oxygen storage tank 65.. For oxygen storage tank-s of 20 liters content, the rate of evaporation of liquid oxygen is about -10% per hour, depending upon the quality of the' insulation layer 46 and the thickness ofthe layer. This minimum evaporation rate accordingly establishes the minimum rate of evolutionV of gaseous oxygenof the apparatus 'and is nearly constant for all temperatures met with in practice. .If it is assumed that the apparatus is used as a source of oxygenl for aviation purposes, the

aviator adjusts valve 33in accordance with altis tude so as to provide himself with an adequate oxygen supply, and accordingly consumes oxygen which Vis drawn off .of the apparatus throughoutlet 5|. Asthe pressure within .tank 35 gradually decreases, this pressure, being communicatedto Y the underside of diaphragm 84,p'ermits the diasupply a uniform evolution of oxygen during descent of aircraft from very high altitudes such as 30,000 feet or more to lower altitudes..

It may be pointed out by way of explanation that when an aircraft carrying an openv container of liquid oxygen increases its altitude, there is a very rapid evolution'of oxygen from'the open vessel due to the decrease in air pressure at high altitudes. This'decrease in'air pressure reduces the boiling temperature of thev liquified oxygen in the open container. `y*This cools the liquid oxygen,

andl should the aircraft .then start to descend, the cooled oxygen would cease to lboil-since the temperature of boiling increases with decreases in altitude more` rapidly than. the chilled liquid oxygen vcould absorb heat. Consequently euolution of oxygen ceases from an vopen container of liquid oxygen during the period of descent. Experiments with open containers for producing oxygen supply for aviation purposes have therefore been unsatisfactory because the aviator is deprived of an oxygensupply for aperiod frequently as muchas several minutes during descent from high altitudes. In applicants apparatus, a nearly constant absolute pressure is maintained, 'on the liquidoxygen. Hence, this craft does not occur.

Since the oxygen which is vaporized within.

phragm to 'flex downwardly thus closing .the-port 81 and closing off the liquid oxygen storagetank 65 from. all communicationwith the gaseous oxygen pressure tank 35 except through tube 63.

As the liquid oxygen continues to be-vaporized a slight differential pressure with respect to the pressure of tank 35, is built up. within tank 65 and accordingly the liquidfoxygen .is `forcedupy wardly through the tube63 until it spills from the outer end of the tube directly into the container 35 where, due to the -large amount of sensible heat available, it isv quickly'vaporized again raising the oxygen gas; pressure within tank 35.`

Consequently valve'BO is again. opened when the pressure of tank 35 reaches thev predetermined .adjusted minimum.l When valve 80 is open, the

gaseousV oxygen evolved in-fcontainer .$5 isipermitted to escape into container. aspreviously explained, and'liquid oxygen is no longer spilled over `-through tube 69.` The cycling.. above described, i-s repeatedfrom time to ,time so long as the demand for gaseous oxygen (i. e.; withdrawals Vvia tube 48) exceeds theminimum rateoi' evoluy "tion due to the heat inflow to theliquid oxygen storage tank 65. It'may be pointed out-that since diaphragm 84 of the valve 80 is spring gloaded, the pressure'atY which itV operatesis not substantially varied by; variations in external pres-sure upon the Vupper side Iofthe diaphragm. 'Ihe space above tliediaphragm is preferably evacuated to the-enectofreducing temperature variation.

Tube 69 terminates outside or nei insulation i 46 at a, level above the maxix'numlevel :of the tank 65 is very cold and is returned to 'the inner v surface of insulation layer 46, the outside passage lof such gaseous oxygen through the insulation liquid oxygen'in tank 65. *This isfimportantso as to prevent syphoning once the flowf liquid oxygen through tube 69iss ta.rf t, ed. l g l In aircraft. uses, the apparatus lis not` always used in the vertical lposition.illustrated AinFigure 3-since the aircraft may move Vfreely in'its element.; This is not disadvantageous to the operation of theapparatus because the 4plane does not fly upside dwn 'for any-.considerable length of time and-the reserve of compressed oxygen gas inside the apparatus is usuallysuiiicient for periods of inverted night. Furthermore, while the apparatus is in an inverted condition, tube 69 serves 'as `a ventrather than as a liquid oxygen outlet tube and V-since the liquid .oxygen or some of` it will bein the uninsulated tube 60 andthe filler neck v59, the'rat of evolution of `gaseous oxygen will be considerably greater -duringupside down flight than during.' normal level i'ght and this. gaseous'oxygen will be' freely vented through tube 69 in such inverted condition. When the,

apparatus is again brought to the Tupright posiv tion shownr` in Figure 3',it'resumes normallevel operation.Y 'Y v l `The filter 49 is important where the oxygen supply is used for human respiration. It .may be f f pointed out that'in the production of liquid oxyf` gen, theVVV compressors used'are frequently lubripression a certain amount vof oil Viscarbonized or iburned and Vinevitably its wayirrtolthe finished liquid oxygen product.v Where the liquid oxygen isy permitted tor evaporate 'from Ya. cont'ainer',Y the undesirable small fractions ofburned oil' remain so chilled thattheyvarenot normally evaporated'while there is liquid oxygen' present.

,Into thefiller neck l and extends to thebottomv of a gaseous oxygen pressure tank 90.

y l |05, there is threaded a nipple |20, which isfheld in Vplaceby a lock nut |2| yseated upon Awasher v|22.Y The lower r,end of 'the nipple has a heavy resilientrubber coupling f cated with vordinary petroleum products anddue tothe high temperatures `attained during com- |23 attached thereto in pressure-tight relation vand'rtor the 1lower rend ofk the nipple, there is attached the neckr |24 of a vacuum-wall flask, generally designated |25. The flask may be of any f shape but is preferably of a spherical design hav- However, as the liquid A oxygensupplyis spilled out, a certain amount of burned oil will likewise beejected and this amount vincreases in concentration astheoxygenfis evaporated off.. The

' lburnt oilodoi` is :very nauseating and'is veryun- Y desirable where the oxygen lsu-sed for human respiration. The lter'40 of s ilicagel; activated carbon or a combination of both rernovesfthese odorsand makes the use ofthe apparatus prac-` tical and safe; v Y

The'apparatus illustrated in Eigures'; ,5 and 6 is especially adapted, notr only for aviation use and particularly militaryaviation use, but may also be usedfor lling oxygenccylinders rwith oxygen gas under pressurelfAs .illustrated in Figure 4, the apparatus consists oiaheavy-,walled gaseous oxygenstorage tank, generally 'designated 90, haz/ing a heavy cylindrical, sidewall 9|, a downwardly bulged endwall 9 2. Thetank is provided with a heavy metal cover, .generally designated 93, which may' beheld-in placefby a plurso ing an inner wail |26 and an outer wall |21 spaced from each. The space is evacuated so as to form a'good heat insulator and `where the apparatus is used for vmilitary aircraft, the evacuated space is preferably completely devoid oi any combustible material such as carbon", Upon the neck of theviiask, therefispositioneda perforated trayl|28 having a., porous material |29'thereon for apurpose to be described.; The ask is of such dimensions so that when'the cover 93 with the ask hanging therefromis lowered into the tank '90, theiiask will'r'est on a cylindrical support 3|, which has a rubber' beading|32at its upper edge. The-nipple supports a liquid oxygen spill-Y over tube |33 Ywhich extends from the lower por- 'Anautomatic valv;"generally designated |40,

is provided forcontrolling, the conversion of the Y. liquid' oxygen to the'Y lgaseous oxygen. The valve rality of screws or clamps 94. The cover 93 seats upon agasket 95 or upon a ground or sealedv l joint depending Aupon the pressures encountered. j

Cylindricalfsidewalls are vprovided with feet 96 where the apparatus.v is bottom-mounted, or may, be provided with hangersrfor wallmounting, ifl

desired.

The `,cover n 93 r is provided' with-nan outletand filter tube- 98`having altering material 99 of |40 comprises a"casing|4 of gastight construction-havin'ga sealedSylphon bellows |42 therein, whichrnay be evacuatedif desired. The Sylphon bellows' is provided withi'an adjustmentrscrew collar v|43 byv which the lpressure at which"l the Sylphon bellowsioperates mayfbe varied. Casing silica gel, .activated carbon or a combinationcil both for theremovalof odoriferous' materials.k

The outlet tube 98-terminates in injunction T |00, Vhaving the consumers tube |`0| and Va, variable over-pressure, exhaust valve, generallyjdesignated |02, which is of the same-type described gauge, generallydesignated |03, and with aseo- |4| isconnected by means yof .tube |45 tofthecou-v Vplingfr- |00 andfrhenc'e'the pressurejwithin the casing |4 |"is the same as the gaseous oxygen pressure ink tank 90.l Sylphon bellows 42 operates upona sleeve-type valve element |44,i`whi`ch serves to close valve seat |46. The -antrurn chamber |41 of the valve isconnected by tube v |48 to the port ||3'o1' thevalve |08, andthe valve outlet |46 is similarly'connected by tube |49 topassage 2 lin with reference to the .apparatus inFigure 3. The

cover 93 isvalso provided with a tank-pressurev ond over-pressure release valve, generally designated |04, which isfset to operate at a pressure above that Vat whichjthe release valve |02 operates. The valve |04 ismounted upon an integrally cast iiller neck |05, which is provided'4 with a'combinedscrew plug and i'lllerV gaugel |06 of the type ldescribed with reference to the'l jap paratus shown-in Figure 3.v K I ,r y

The coverg93fincludes the housing of an 1in# tegrally cast 3position` valve,l generally' desig' nated |08, which has-a drilled passageway |09f extending into' the ller neck as shown atn |0.4`

The outer end of the passageway |09 ig plugged f withy Va screw "I and thereare drilled'branch is rotatably mounted'in the valve easing |08 and cooperates with the various'drilled Dassageways The to provide three different valving conditions.. v tubular connection connectsto passage H5 valve |08. l l y The valve |08 is capable of being placed in three operative. positions illustrated in Figures 4,' 5 and y6.- kThe operation or the apparatus is as follows:'

It is assumed thatthe apparatus has no`liquid oxygenin it and has been out of service and is therefore'l. at ambient;Vr temperature. The tank over-pressure release valve |02 is adjusted vto a low pressure'a'nd the three-position :Valve |08 is adjusted to the position shown in Figure`5. The

combinedplugand'- liquid level gauge |06 is re moved and liquid oxygenis poured into a iiller f neck untilA the vacuum fflask '|25 is full, or nearly Vfull. The 'liquid level gauge'and plug arefthen refinserted and vscrewedfdown until gas-tight.

rDue to thesensible Yheat ofthe apparatus liq'uid oxygen n initially eva'porates at an exceedingly f rapid rate thus vap'orizing considerable amounts of oxygen'which are evolved through the neck-.of f thefiiask and thence through port |0 through the valve |08,wh`ich is,v`as previously stated, in

the initia1ni1ingposition snownin Figure 5 4and thencer through tube to the interior of gaseous oxygen .pressure tank 90. AThe gaseous oxygen builds up a pressure in the entire apparatus until it begins to vent at the over-pressure release valve |02 or until use of the oxygen is initiated; The

over-pressure release valve is then Vadjusted to the working pressure of thegappa'ratus which, for

aviation purposes, is preferably` aboutv 60 pounds per `square inch,r absolute.v When thelworking pressure is built up, valve |08 is moved to the normal position shown in Figure 4 andthe apparatus isinoperation. The insulation ofthe vacuum-wall' yflaskjis' very eiilcient. For a ilask of 20 liters capacity, the rateV of evaporation'due to inllowof heat. through V.the flask Ywalls is approximately`2% "ori 0.4`liter of liquid oxygen,; for each 24 hours, or

in other words, a. filled 20 liter ilask willV be empty atfthe end of150 days' if noneofjthe liquid'oxyure V4.1'The gaseous oxyeen'hencepasses through' port f| |3tub' e |48, through t.the normally "open automatic valve |40, lthence through i lube I 49, port ||2, through 'thefvalvegplug .Iia, portl||5 andlthence'throughtube to the'` interior of. the gaseousoxygen storage' tankv 9,0 where ity serves ,toy maintain .pressurewithin vthe tank.

If no Withdi'awals' .V are made; the pressure grad-` ually increases Auntil theover-pressure release valve |02 operates. yOver-pressure. valveu |04 acts as anextra safety valve. Wlien oxygen isf-consumed the tank decreasesjprovided thefrateof-withdrawal is faster than the minimum rate of evo- Q lution of Voxygen andas the pressure dropsA to a predetermined', the Sylphon Ybellows |42'of automatic valve `|40 expandsdue to the czorr'espomiing` decrease in pressure within the casing` |4I. TheSylphon bellows |42 is sealed and may contain av resilient gas or preferably `be withdravvzil.r through nner esami tube whine pressure mv flask. The liquid i oxygen thus: evaporated rapidly builds up pressure within tank and since tank 90 is connected by pipe |45 to bellows chamber. |4|-. the pressure fcauses the Sylphon bellows to `contract thus opening valve |46, `which in tur'permits the oxygen .vapor pressure in |25 to become equalized with thatoftank 9D. Liquid V oxygen is therefore no longer delivered through tube |33. As the pressure again drops. the cycle of delivering liquid oxygenjto the interior` of pressure tank '90. for evaporation therein is repeated'over and-over' as long as the supply of liquid oxygen lasts and withdrawals continue. i A

The'fllter 99 `like `therlilter 49 inV Figure 3, serves to'collect andV hold'all odoriferous materialrs'fthus making the supply of gaseous oxygen safe and comfortable for' humanrespiration.

When the" liquidlevel gauge inthe plug |06 indicates thatthe liquid level has decreased'to,

a low level, andit isldesiredV to relillfilaskA |25,

this may conyenientlybe done without interrupting the `oxygen supply delivered fat tube |0| fto the aviator orgother' person using the apparatus. The apparatus illustratedin Figures 7, 8 Aand 9 is especiallyladapted for supplying oxygen gas from-liquid oxygen supply in hospitals vand. theA like, although bysuitabIe modication'it may b'e-easily adapted for military uses'where armor is ofl paramount importance. The vapparatus consists of `a rectangularbox, generally designated |50,jpreferably made of sheet metal, having a topl cover |5|1,.` an intermediate Vpartition |52, lsidewalls |53" and |54',V an endwall |55 and aY hinged "endwalln |56. opened duringfuse 'of' the apparatus and may be perforatedto allow warm'air to come 'into evacuated and may expand due to an internal i bias spring onnatural resiliency of the bellows. The adjustmentis such Vthat the bellows operates and moves valve-slide |44 to the seated orf closedfposition upon `valve seatV |46 when the pressure within tank 90 has decreased toa predetermined level. When valver|40 has'V closed, the gaseous oxygen Vevolved Within tank |25v is no longer vented tn theinterior of the pressure tank 90'ar'1d gradually builds up a differential pressure within the vacu'umiiask thus causing the liquid oxygen to rise inA tube |33 until it is spilled fout ofthe end ofthe tube vand.deflect-7.4.65

ed'down by deilector plate |36. f

The liquid oxygen spills upon the porous` material |29 where it is evaporated. Y VIt may be noted that Athe Vliquid oxygen.Y is very cold as compared with the exterior ilask wall 2'|, Vand it is` therefore. desirable'not toallowV itfto fall on'to"the walls of'either container 90 orfiask -in the surrounding space, thus causing a contraccontact with the apparatus.' AInl the compartmentbetween' theintermediate partition |52 andendwall |55; there is supported a storage flask of strong steel," generally designated |60, having a wall |6|- `The`flask is'supported upon afdish '|62 vwhich isspaced-:slightly from the Wall |6| and touches theask wall at various- Y places around theupper edge of the-dish. The dish-and wall are not sealed air-tight. The

' disais provided with adram iss leading downwardly to. the space betwee'nfpartition |52 and endyvall |56V andthe dish'ls supported on cylin- '50 A Y drical frame |63'. i

The large compartment between walls |52 and |55 is air-tightexcept for tube |60 and flask |60 is thoroughly insulated by a packing of, kapok, rockwool or glass wool lll. When liquid air-is poured into. iiask |60, it reduces the temperature tion of the air wit'hin theinsulation and a consequent drawing in off-air through tube |68. As drawn in, the airsim-pinges upon Vthe extremely cold surface of flask wall |6| and-moisture is frozenY out and collected between' wall 6| and dish |62.

the insulation mass. Whenfthe apparatus subsequently becomes warm,.the moisture in'dish |62 is theiirst to be expelled,` and moisture satu ratedairls expelled through, tube |60until .all i y moisture is` removed.r Tube |68 `drains'intothe |21 since it might cause'thew'alls to1 contract 1 and crack. `The porous material I 29" serves to ration without any adverseeiect in the vacuum Vdisperse the liquid oxygen and cause its' evapo-` i smaller `compartment whence it `again drains .throughtube |64, togeth'er with? water condensed on the apparatusV in that compartment.

The flask 60V is Vprovided with two n ecks, along neckrul66, which extends through-cover 15|, and f ashort neck `|61V which is 'within thecontalner. The long neckv serves; as a illler opening and is capped by a plugY |69 which carries a liquid level Endwall l|56 may be Hence, only yery dryair illters into gauge Aof th'e spiral type hereinbefore referred to. The short neck-|61 o1' flask |80 is provided 'Y witha stopper |12 through'which' two tubes extend. One-oiv the tubes |18 extends through the stopper |12 to nearithe bottom offi'lasrk |60 and the other tube l|16 Aextends through the stopper to the upper part of vflaskl |60. 'Both'tubes extendacross the upper portion of ther apparatus and through'the partition |52 asillustrated in 'Figures 8 and 9, and into theend compartment between partition |52 .andthe removable cover Within the vend compartment are three cylinders |18, I19`and |80. Each of the cylinders vhas endwalls which are weldedior otherwiseheld in place.:` 'Ih'e tubes |15andf|16'extend through `the uppercover of the cylinder |18, tube-|15 extending about midway i'ntothe cylinder while tube`i|16 'terminates'at o'r slightly below -th' e .topj vcover |8| Aforming a valve seat. .Withincyllnf" der |18, there is a cross` frame |82 which serves. to support a Sylphon bellows |83, which actuates a valve element |84, aligned with theu end 1o! tube |16. rThe Sylphon bellows 83is sealedand is preferably evacuated' and may contain a residual gas or internal spring. The bellows is responsive to the pressure withincylinder |18; Asfthe'pressure `decreases, thebellows expands' and forces the valve element,4 |84 into contact with the valve seat end of tube |16 thereby clos` ing off ow through that tube'.

It'will be noted that the frame I 82 is apertured so that thepressure within cylinder |18 is constant throughout. u t'here is afcross frame |86 in vcylinder |18, which serves *to break up and finally disperse vliquid oxygen fallingthereon. The lower portion of cylinder |18 is connected by means of an oxygenv kthe storage. ask.

vacuum waneaif desireais' dependent ambient temperature ybut .is substantially constant for the range of temperatures met with' l in practice. `Accordingly," there `is a gradual boiling-.away of the liquid oxygen within the flask 6 0 at a ratek dependent upon the heat inow into f .Valve 20| is then closed but sincepressure has not developed in the system, the bellows |83 is 'expanded and the venting tube |16 is closed by valve element |84. Consequently@ differential "pressuredevelops lin the vacuum flask |60 and cause'sgliquid oxygen to rise in tube-.|15 and overflow directly into cylinder |18 where, due to the largefsensible heat available, .the liquid' oxygen is quickly vaporized. vThe gaseous o xygent'h'us .evolvedbuilds .upthe pressure, Vnot only in cylinder |18,` but also throughout `the Lventire system including cylinders 19 fand,|80 andilaslr |60 until-suHcient to cause a' contraction of vvthe sylpimnbeuows Vlas tuus openinsvent tube |15. When so opened, tubev |`16 ;p ermits an equalization ofipressur'e'pf cylinder |18 as compared with i vthe pressure'of flask- |60/and liquid oxygenis Below the end of tub'ens,

thereforenolohgerraised in .tube .|15 and spilled over. inte Cylinder-|18. Y The.-gradual evolution fof. oxygen maintains a pressure and `if oxygen-is notjwithdrawn at valve 20|, the ,pressure will gradually..increase Yuntil oxygen is vented at the over-pressurerelief valve 200.. Where oxygenis withdrawn throughvalve .20| at farate greater than the minimum rate of evolution produced by the inflow of heat into ask |60,there is a consequent lowering of the pressure lin the system and asA -the pressure reaches a y predetermined adjustable minimum,

delivery'tube |88 to the upper portion of lcylinder' |19, which has endsc'reens |89 and |90 between which there is a, filter" packing |9| of'silica gel.

"The lower'portion of cylinder |19 is connected by means of an oxygen delivery tube |93 to'the lower portion of cylinder |80. LCylinder-||30 like.- wise is provided with screens |94 and |95 between which'there is a lter packing V|96 o f vactivated carbon. The silica geland activated carbon ljjters very effectively collect and 'hold odoriferousv materials t'h'us purifying the oxygen gas so that' it may safely be used lfor human` respiration.

` Other ltersfor the 'saine purpose may obvious Y the apparatusk pre# ly -be used in this 'or' any of viously described;

depending upon the ladjustment of 'fSvylph'on bel= lows' |83, the vent; ytube *|16 is Y again closed olf by the action of valve |84. The differential press ure again builds .up within thevacuum ask |60 causing .theliquidoxygen to rise intube |15 and ,thereby spilled into cylinder |18,Q'again' raising the pressurer inacc'ordance with the de-` mand .even though `the demand is variable.

. The cyclic operation continues more orless rrapidly in accordance with the demand, however.variable,y until lthe liquid voxygen supply is exhausted at `which time the ask v|60 is again' vopened andrefilled, crit may be refilled under. pressure o'ratvatmospheric pressure by the provision of suitable valves, inlets, etc., as herein described- The cover |91 of cylinder |80 is provided with a pressure gauge |98v and with an outlet tube |99;Y The outlet tube 'l99`car'ries an over-pressure relief valve 200,1and a shut-off valve v20| terminating in4 oxygen; delivery noz le `202. space between the row'of cylinders |18, |19 and |80 and the door |56 may conveniently be usedfor a, coiled delivery hose y203held in place on `clips 204, if desired. f

The operation'of the apparatus illustrated in Figures 7, 8 and 9 is as'followsi ,Y y I'he plug |69 or the liquidlevel gauge carried therebyjis removed from the filler neck |.66and liquidoxygen is poureddntotheask until. it is full or nearly full. As the apparatus .maybe warm, theevolutio'n of oxygen is rapid for; a'` short time until atfleastthe interior A.portionslof the flask |60 are chilled to the temperature of:v .v liquid oxygen. The valve 20| lsithen' opened and the plug` |69 and attached liquid level gauge are inserted in the filler neck v|66 and made fast. The inflow of heat to the flask |60 which may be armorplate. l

f-`Where thefapparatus 'illustrated inHFigures `through 9 is' used 'for' military purposes,y armor y maybe applied .either tothe outer boxf|50 or by making 'the ilaslr |60. and the oxygenfcontaining cylinders and tubular connectionsjofgheavy'- steel `For vreiilling theapparatus withliquid oxygen,

timeiby'exheue nsihesaseous the '@barema,fshcwntfin Fi.

55, and; fth'enf the liquid .o`

' the. V3-positio'n valve .108; is'.movedtojthe posi-.j` M

tion shown in Elgure 16, thus closing the passageway v| |Sfand-ccnsequently closing 'oilfiow of gas through that passage to' theinterior of flask |25.

At the same time, thelshut-otf valve|31 is moved entire container since it not only directly vents the vacuum-wall flask |25, but also. vents vthe oxygen pressure tank 90by virtue Vof the normally opened connection to tube |513.V however, a.AV small interval between the time cap |06 is screwed tight and .valves |31 vand |08 moved to their `normal operating` positions during which `pressure maybuild up within theflask |25. TheV over-pressure release valve |04 thus serves, duringV this interval, to act as a' direct,

vent for the vacuum flask |25.

Other methods of-filling may also be usedfor any ofv the systemsherein described. As illustrated in Figure 10,the liquid oxygen supply may be transferred from the extra supply vacuum storage fiask HAinto Vflask |25 while the latter The plug and liquid There iS,

is under working pressure. AThis is accomplished by means of a simple permanent or temporary tubular connection ||9 reaching from the bottom of the extra supply flask ||4 and Vconnected to valve |01 which is opened when the transfer is being made. The extra supply flask H4 is stoppered and a pressure is built up sufficientv to overcome the working pressure in tank |25. This pressure in the `extra supply flask can be built up byY a pump or by generation of Vgaseous oxygen pressure by heat inflow or by applying heat to the inside of the flask as byV a small electric heater element ||8 which, `being easily controllable by means of a switch or rheostat evaporates a` small amount of oxygen, builds upa pressure S in 'flask ||4 and forces the liquid oxygen against the Vworking pressure of tank 90 `and into flask |25. Many variations in the apparatus and method Ywill be obvious 'to-those skilled in the art and are deemed within the purview ofthe invention herein illustrated, described and claimed.4

We claim as our invention:

1. An 'apparatus for converting oxygen fromy the liquid to the gaseous phase in accordance with a Variable demand and'underpressu're comprising a pressure tank for storing the gaseous oxygen, a port in said pressure-tank vfor drawing off the gaseous oxygen, a liquid oxygen storage tank withinthe pressure tank, insulating spacel around the liquid oxygen storage tank and means automatically responsive to a decrease in pressure of the gaseous oxygen within the pressure tankior transferring liquid oxygen directly from the liquid storage tank'into the pressure tank for evaporation therein.

2. An apparatus for converting oxygen from the liquid to the gaseous phase in accordance with a variable demand and under pressure, comprising a pressure tank for storing the-gaseous foxygen;

a port in the pressure tank wall for withdrawing gaseous `oxygen therefrom, a smaller liquid'oxygen storage tank consisting of a vacuum-walled pressure tank, e tube extending from the interior of the flask to the internal spacebetween the flask and the pressure tank wall, and means automatlcally responsiveto the pressure ofthe gaseous oxygen within lthe pressure tank for closing `the vent passage when the pressure decreases to a predetermined minimum. Y g Y Y 3. The apparatusset forth in claim 2 further characterized inthat the pressure tank has `a removable end lid which provides the` principal mechanical support for the elements other than the pressure tank set forth in said claim.

4. An apparatus for converting `oxygen from ,the liquid to the gaseous phase inaccordance-with a variable demand and underfpressure comprising a pressure tank for storing the gaseous oxygen, a port in Tthe pressure tank wall for withdrawing vapor oxygen therefrom, a relatively smaller liquidoxygen storage tank positioned inthe interior of the pressure storage tank,-a foraminous heat insulating covering for the liquid oxygen storage tank, a passageway from the interior of the liquid oxygen storage tank and above the liquidrlevel `thereof to a.A position adjacentthe outer surface o f said liquidoxygen storage tank and adjacent the inner surface of said insulating covering whereby cold gaseous oxygen may be delivered to the inner surfacerofthe insulating material for outward filtration therethrough, and means responsive to decrease of gaseousoxygen pressure in the pressure tank for discharging liquid oxygen directly from the liquid oxygen `storage tank to the pressure tank for direct evaporation therein. i

5; The apparatus ofl claim 4 further characterized in that the means responsive to pressure changes inthe pressure tank include a liquid oxygen delivery pipe from the interior of the liquid oxygen storage tank to the pressure tank, a valve in said passageway and means responsive to tliegaseous oxygen pressure for closing-the passageway when the Vpressure in they pressure tank decreases below a predetermined point.-

Y6. `A11-apparatus forl converting oxygen from the liquid to the gaseous phase in-accordance with a variable demand and under pressure comprising-a pressure tank' for storing gaseousoxyf gen, a port `in the pressure tank wall for withdrawing gaseous oxygen therefrom, a relatively smaller.,liquid'oxygen storage tank positioned in the interior ,of the pressure storage tank', a supporting frame having openings therein v@vering the walls of the liquid oxygen storage tank vandv spaced therefrom, a thick layer ofV insulating material over the frame formingan insulating covering for the'liquid oxygen storage tank',4 a gaseous oxygenvent line from the liquid oxygen storage tank to the pressure tank, said line `having an automatic valve therein,` a liquid Oxygen delivery line from the liquid oxygen storage tank to the pressure tank'for delivering liquid oxygen thereto and means responsive to a decrease in 'gaseous oxygen below a predetermined point in the pressure tank for closing said automatic valve whereby increased pressure inthe liquid oxygen storage tank causes discharge of liquid oxygen into the, pressure tank for direct evaporation therein.

f7. The combination set forth inclaim 6 fur-` ther characterized in that said valve and means the remaining elements set forth in said claim. except the pressure tank, so that said elements are removable from the tank when the end lid is removed. y

9. An apparatus for converting oxygen from the liquid to the gaseous phase in accordance with a. variable demand comprising a liquid oxygen storage tank and a gaseous oxygen storage tank, a valve line connecting the said tanks for conveying liquid oxygen from the liquid oxygen storage tank to the gaseous oxygen storage tank, and means responsive to the pressure of the gaseous oxygen for opening the line when the gaseous oxygen pressure decreases below a prescribed amount and for closing the line when the gaseous voxygen pressure increases above said predetermined value.

10. An apparatus for converting oxygen from the liquid to the gaseous phase in accordance with a variable demand comprising a liquid oxy- -gen storage tank and a gaseous oxygen st orage 18 with a variableldemand comprising a, liquid oxygen storage tank and a gaseous oxygen storage tank, a line for conveying liquid oxygen from the lower part. of the liquid oxygen storage tank to the gaseous oxygen storage tank, a valve in said line for opening and closing the line, means including an airtight bellows responsive to the absolute pressure within the gaseous oxygen storage tank for opening said valve when .the absolute pressure of the gaseous oxygen in the gaseous oxygen storage tank decreases below a predetermined minimum.

JOHN D. AKERMAN.

JEAN F. PICCARD.

REFERENCES CITED The following references are of record in the iile of thisl patent:

UNITED STATES PATENTS France July 17, 1931 

